Is The Google "Yo-Yo Effect" Due to Universal Search?

About 15 days ago, I reported on the Google Yo-Yo Effect. This yo-yoing is a lot different then the typical ups and downs of Google's rankings. I know many of you are going to say, Google's results always differ. Trust me, I have been covering search a long time, this is different.

Over the course of the weeks, I have obtained results that are experiencing this "yo-yo effect." I am sorry, but I promised not to share the actual results. But I can tell you, this is real. Let me explain what I see with the fictitious keyword phrase [blue widget] and domain acme.com.

Acme.com has been finding itself ranking well in the morning hours for the keyword phrase [blue widget] over the course of the past few weeks. But it is only the morning hours. After the morning hours, acme.com's Google rankings for [blue widget] drops to the third page or so. Why? It is not known. But the pattern continues each day for the past few weeks.

There are some theories, as Tedster summarizes in WebmasterWorld. Here they are:

Maybe Google is counting clicks and after X number of clicks, Google is pushing that result back.

Maybe this has to do with Google Universal Search and the position acme.com shows up for correlates to the universal search spot?

The first theory just makes no sense. Why would Google cap a specific page from getting more than X clicks per day. It just doesn't make sense to me and to most people.

The second theory might just fit. Tedster notes:

Watch that #4 position on the SERPs that don't have Google News in the spot. It seems to be the position of choice for some kind of testing. I see urls that yo-yo between page 2 and position #4 during different times of the day. Then the SERP sometimes changes and Google News is back at #4.

But it's always #4. Universal Search technology, I assume, allowing Google to force feed certain tests into specific positions - maybe even the same kind of goodies that blew up a few months ago and gave us the position #6 bug.

Maybe Google is testing throwing in certain pages into the universal spot, as a test? Or maybe it is the opposite? Maybe Google is giving up the #4 spot of acme.com for [blue widget] and pushing acme.com to the third page?

It just doesn't seem like normal Google behavior. It just doesn't seem like a "feature," but more like a bug. It would not be totally unreasonable to suggest Google does create bugs, accidently, that appear to be some sort of ranking algorithm or penalty. Just take a look at the minus 6 penalty bug, which was reversed.